title: Unimpeded tunneling in graphene nanoribbons.
abstract: We studied the Klein paradox in zigzag (ZNR) and anti-zigzag (AZNR) graphene nanoribbons. Due to the fact that ZNR (the number of lattice sites across the nanoribbon = N is even) and AZNR (N is odd) configurations are indistinguishable when treated by the Dirac equation, we supplemented the model with a pseudo-parity operator whose eigenvalues correctly depend on the sublattice wavefunctions for the number of carbon atoms across the ribbon, in agreement with the tight-binding model. We have shown that the Klein tunneling in zigzag nanoribbons is related to conservation of the pseudo-parity rather than pseudo-spin as in infinite graphene. The perfect transmission in the case of head-on incidence is replaced by perfect transmission at the center of the ribbon and the chirality is interpreted as the projection of the pseudo-parity on momentum at different corners of the Brillouin zone.
authors.affiliation: Department of Physics and Astronomy, Hunter College of City University of New York, 695 Park Avenue, New York, NY 10065-50085, USA.
authors.forename: O
authors.initials: O
authors.lastname: Roslyak
authors.forename: A
authors.initials: A
authors.lastname: Iurov
authors.forename: Godfrey
authors.initials: G
authors.lastname: Gumbs
authors.forename: Danhong
authors.initials: D
authors.lastname: Huang